Okay, so I'm a bit stumped.

I am trying to create a trigger on an already defined table that uses a GUID (uniqueidentifier) for a primary key.

I need to take the generated GUID and associated it to an INTEGER (which is an identity seed column).

I now have the following, I just want to make sure it is appropriate and that there isn't a better way. I can't redesign the original table (trust me, I tried!), so I have to work with what is there. The below seems to work.

Code:
USE GainWeb;
GO
IF OBJECT_ID('MyReferenceTrigger', 'TR') IS NOT NULL
	DROP TRIGGER MyReferenceTrigger
GO

CREATE TRIGGER MyReferenceTrigger ON MyTable
AFTER INSERT
AS 
	INSERT INTO MyReferenceTable SELECT UniqueIdentifierColumn FROM INSERTED
GO
Here is the definition of MyReferenceTable
Code:
CREATE TABLE MyReferenceTable
	(
	NewAutoSeed int NOT NULL IDENTITY (1, 1),
	OriginalUniqueIdentifier uniqueidentifier NOT NULL
	)  ON [PRIMARY]
GO
ALTER TABLE MyReferenceTable ADD CONSTRAINT
	PK_MyReferenceTable PRIMARY KEY CLUSTERED 
	(
	NewAutoSeed 
	) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

GO